Commission V Symposium, Newcastle upon Tyne, UK. 2010 PHOTOGRAMMETRIC DETERMINATION OF SPATIO-TEMPORAL VELOCITY FIELDS AT GLACIAR SAN RAFAEL IN THE

• Main Authors: Northern Patagonian Icefield, Hans-gerd Maas, Danilo Schneider, Ellen Schwalbe, Gino Casassa, Anja Wendt
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: KEY WORDS; Terrestrial image sequence processing; glaciology; photogrammetric network ABSTRACT; Austral; Tidewater
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.221.7979; http://www.isprs.org/proceedings/XXXVIII/part5/papers/121.pdf

The paper describes an approach to determine spatio-temporal velocity fields at Glaciar San Rafael in the Northern Patagonian Icefield by terrestrial image sequence analysis. It discusses image acquisition schemes and concentrates on aspects of glacier surface feature tracking, georeferencing and trajectory precision. Glaciar San Rafael in the Northern Patagonian Icefield, with a length of 51 km and an ice area of 722 km 2, is the lowest latitude tidewater outlet glacier in the world and one of the fastest and most productive glaciers in southern South America in terms of iceberg flux. In a joint project of the TU Dresden and CECS, spatio-temporal velocity fields in the region of the glacier front were determined in a campaign in austral spring of 2009. Monoscopic terrestrial image sequences were recorded with an intervallometer mode high resolution digital camera over several days. In these image sequences, a large number of glacier surface points were tracked by subpixel accuracy feature tracking techniques. Scaling and georeferencing of the trajectories obtained from image space tracking was performed via a multi-station GPS-supported photogrammetric network. The technique allows for tracking hundreds of glacier surface points at a precision in the order of one decimeter and an almost arbitrarily high temporary resolution. The results show velocities of up to 16 meter per day, which is in accordance with former measurements. A significant tidal signal, as theoretically predicted by other authors, could not be observed. As a by-product, a maximum value of 55 meter could be determined for the glacier front height. 1.